We intend to continue retrograde catheterization of the carotid artery of goats with catheters. Each catheter will be treated with goat albumin which has been prepared to contain single different fatty acids. The albumin will be "bound" to the catheters by glutaraldehyde. Studies will be done to measure desorption kinetics of albumin and the fatty acids using radionuclide tracers. Retention of platelets onto the carotid catheter will be assessed acutely and continuously using III Indium labeled autologous platelets. Work will also begin on correlating differences in III Indium accumulation among catheters and correlations with thromboembolic material measured in Biomer arterial grafts implanted chronically.